ultradian

We have been hearing about the circadian rhythmsand we know well that the blue light from screens before sleeping is bad or that the melatonin sends at night to induce sleep. However, there is a second biological clock that is much less talked about, but which dictates exactly why at 11:30 in the morning we feel invincible, but when 1:00 p.m. arrives we cannot keep our eyes open to work. These are the ultradian rhythms. Its foundation. Far from being an invention of productivity gurus, the existence of these rhythms is deeply rooted in our physiology and hormonal secretionespecially during sleep. But the important thing is that understanding them will not give us superpowers, but according to scientific and neurobiological literature, it does explain how the brain “battery” works. What are they? To understand ultradian rhythms, we must travel to the 1950s and focus on Nathaniel Kleitman, the pioneering researcher who discovered REM sleep. At this point, Kleitman and his team realized that we don’t sleep in one uniform stretch, but rather our night is divided into cycles that last between 90 and 120 minutes. During each cycle, we go through several stages, such as light sleep, deep sleep and also REM sleep. Once we reach this we start again, and this is what is known as the ultradian rhythm. It is maintained. Logic could make us think that this cycle remains only in sleep, but here Kleitman postulated the Basic Rest-Activity Cycle (BRAC). With this theory on the table, it was proposed that this same 90-minute clock does not turn off when we wake up, but rather that during the day our brain continues to operate in waves. In this way, we can see that we have peaks of high alertness and concentration of about 90 minutes, followed by valleys of fatigue of about 20 minutes where the body requires a rest to recover. A hormonal issue. Something that is well known is that the secretion of hormones is not done continuously like an open tap, but in pulses or “peaks” that are synchronized with these 90-minute cycles. For example, growth hormone is essential to repair our tissues and its maximum peak is linked to the stages of deep sleep that occur in the first ultradian cycles of the night. This means that, if these first 90-180 minutes of sleep are disturbed, the body will not repair itself in the same way. Respect the ultradian rhythm. Among the tips we can follow to control these cycles is the 90/20 rule at work. And if we assume Kleitman’s BRAC cycle, the optimal window of mindfulness lasts about 90 minutes and then we enter a moment of fatigue where we do not perform in the same way. That is why it may be best to work for 90 minutes and then take a real break away from the work screen, for 15-20 minutes to reset this cycle. But the moment of waking up is also essential, since feeling tired when getting out of bed usually occurs because the alarm went off in the middle of the slow wave sleep phase or deep sleep. That is why calculating the hours of sleep in blocks of 90 minutes increases the probability that we will wake up at the end of these cycles and be able to get up with much more energy. Images | Vitaly Gariev In Xataka | Neither red light makes you sleepy, nor white noise is magic: what science says about the trend of “hacking” the bedroom